This application is located in the area of battery charging. To determine the end of charge condition of a battery charging cycle as well as for fuel gauge algorithms, it is required to measure the charge current of the battery. Measuring the average charge current is often performed by applying a long integration period. The integration period is typically in the range of a second. This method is suitable for fuel gauging but inaccurate for end of charge detection due to the fact that a current may be pulled out of the battery by a load while charging the battery so that the current measurement could be distorted. For end of charge detection, it is desired to accurately determine the maximum charge current which would flow into the battery if the battery charge current was not influenced by the system load and the power supply's current limitation.
Thus, for an accurate end of charge detection, there is a need for a method and device for determining the maximum and undistorted charge current of a battery of a load modulated system.